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RE: I'm Bored, part ll. MA-1 pictures

The top photo seems to show the gray filter caps for the HV supply. These filter the +/-300V supplies to the input and driver stages. The huge caps in your bottom photo filter the LV supply (around +/-125V) for the output stage. I don't know what you mean by "coupling caps"; are you referring to the Clarity caps that you have in parallel with the big electrolytics?

As to your actual question, there is nothing set in stone or sacred about the total value of the capacitance used to filter the HV supply. You can remove 200uF and replace it with 150uF, if you like. The best way to do this would be if you have an oscilloscope, to see what happens to the supply voltage (which ideally should be a straight line on a scope, with no or very little ripple where the HV exits the filtering) when you change anything at all. I had suggested making a pi filter, but it seems you have limited space and perhaps limited experience to carry that off without an "accident". (I've been there, done that.) Don't do it if you are at all dubious of your level of expertise.

I personally (my opinion) do not think you will hear a meaningful difference if you insert a BG in there. Bypass film caps will do much more for you, or not. On the other hand, those 150uF/350V BGs are smaller than the caps I see in the circuit now. If you have several of them, you might be able to fit a choke as well, to make a pi filter.


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  • RE: I'm Bored, part ll. MA-1 pictures - Lew 08:14:23 03/09/14 (0)

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